A tarpaulin is widely used to cover articles in freight vehicles or warehouses so that the articles are kept safely in even rain or sunshine. Generally, a tarpaulin is used in such a fashion as to be secured at the edge portion thereof by means of a string or rope, and at this time, so as to prevent a tarpaulin fabric from being damaged, eyelets are attached along the edge portion of the tarpaulin fabric and the string or rope is passed through the eyelets. Then, the eyelet and the string or rope are in close contact with each other, so that the punched portion on the tarpaulin fabric can be completely protected, without any damage or tearing out.
It is well known that a tarpaulin is made such that a fabric is formed by weaving weft yarn formed of low-density polyethylene and warp yarn formed of high-density ethylene and the same polyethylene is coated on the upper and lower surfaces of the fabric, and therefore, an explanation of such a process of the tarpaulin will be omitted for the brevity of description of the present invention.
After undergoing the process, the tarpaulin is first folded by a predetermined width along the edge portion thereof for the purpose of the reinforcement of the edge portion, and then, a plurality of through-holes are punched on the folded portion at predetermined intervals for attachment of the eyelets thereto.
Examples of typical eyelets include aluminum eyelets and hard plastic eyelets, and the conventional eyelets are made by using an upper mold and a lower mold.
An aluminum eyelet before mounting is comprised of a lower cylindrical body and an upper disc, the lower cylindrical body having a bottom plate and a cylinder placed upwardly on the bottom plate. The cylinder has a height of about 6 mm to 8 mm. The upper disc has a generally round ring formed in the intermediate portion thereof, the round ring being concave at the inside thereof, and also has a flange turned over around the outer periphery thereof. A method of mounting the aluminum eyelet on the tarpaulin is embodied by using an eyelet-punching machine. After the hole for the eyelet is formed on the tarpaulin fabric, the lower cylindrical body and the upper disc are coupled by mean of a rivet in a rigidly compressed state, and the cylindrical portion of the lower cylindrical body is compressed and molded in a shape of a protruded round loop in such a manner as to be coupled with the inside of the concaved round ring in the intermediate portion of the upper disc. As a result, the lower cylindrical body and the upper disc are formed as an integral body with each other and then mounted on the tarpaulin fabric. The rope, which is used for fixing the tarpaulin fabric, is passed through the inside of the hole formed in the center portion of the eyelet, such that the tarpaulin fabric can be fixed to a given fixed object.
The hard plastic eyelet has generally the same structure as the aluminum eyelet, except that a plurality of protrusions of a predetermined thickness are formed in a shape of a circle on the top surface of the bottom plate of the lower cylindrical body and on the bottom surface of the upper disc. The protrusions are inserted into the tarpaulin fabric upon coupling of the eyelet with the tarpaulin fabric, thereby achieving the rigid attachment of the eyelet to the tarpaulin fabric.
However, such the conventional types of eyelets have had the following disadvantages:
First, the rivet-coupled way between the lower cylindrical body and the upper disc of the eyelet results in the failure of the close connection between the eyelet and the tarpaulin fabric. That is, a clearance between the eyelet and the tarpaulin fabric is left, and if an external force is applied to the rope passed through the eyelet, the eyelet becomes easily loose such that it is moved together with the rope over the tarpaulin fabric. In some cases, the eyelet may be deformed and even deviated from the tarpaulin fabric. Furthermore, the tarpaulin fabric can be torn around the fixed portion to the eyelet, and if it is so, the torn portion can be rapidly extended, which may cause the whole of tarpaulin fabric to be useless.
Second, most of tarpaulin fabrics are made of plastic that is different from the aluminum eyelet material. According to the environment protection requirements prescribed in many countries, when the usage duration of the tarpaulin fabric elapses, the aluminum eyelet should be inconveniently detached from the tarpaulin fabric because it is not recycled, which makes the load of the process increased. On the other hand, the hard plastic eyelet can be recycled, but it should be separately detached from the tarpaulin fabric because of the hardness difference of the materials between the hard plastic eyelet and the tarpaulin fabric.
Third, since the aluminum eyelet and the hard plastic eyelet are all hard, they are easily deformed to undesirably form an edge portion around the outer peripheral surface thereof after the usage of a predetermined period of time, which causes an operator to be hurt on his or her hand when the rope is passed therethrough.
Fourth, the production costs are relatively high.
Fifth, the manufacturing process is relatively complicated.
Sixth, since the eyelet has the different structures between the lower cylindrical body and the upper disc, the parts are delivered individually during the production of the eyelet, and the process of mounting the eyelet is complicated, while having the low efficiency.
Finally, the eyelet has a relatively complicate shape, and since the upper cylindrical body has a predetermined height, relatively large space for the delivery is occupied.